The great ice storm of January 1998 was the worst disaster
Maine has seen in a long time. However, while we humans suffered
greatly from the storm, with more than 20 lives lost, billions
of dollars of damage done throughout the region, and loss of
electrical power for as long as two weeks for some people, by
far the greatest and most enduring effect of the storm is the
extensive damage done to our trees and forests.

Forest damage from the ice storm was widespread
in Maine, New Hampshire, New Brunswick and Quebec.

As everyone knows, trees were decimated throughout the area
affected by the storm, losing branches and major limbs or falling
down completely. Thousands of shade and ornamental trees in yards
and along our streets were lost, some sugarbushes were completely
destroyed and our forests may not be the same again for decades.
Here in Washington County where I live, one can look out from
hilltops and see many large swaths of Larch and Aspen where virtually
every tree has lost its top. As one drives through the landscape,
the fresh scars of missing limbs are visible on trees everywhere
one looks. In the vicinity of Augusta and areas to the east the
damage was even worse, with large sections where virtually every
tree seems to have suffered major damage. However, this massive
damage to our trees cannot simply be blamed on the ice. Other
far more insidious factors contributed considerably to the disaster.
Naturally, heavy ice is always going to bring down some trees
and limbs, but previous damage and stress to our trees and forests
from air pollution made things much, much worse than they would
have been otherwise. Not coincidentally, the species of trees
most badly damaged by the weight of the ice - Maples, Ash, Birches
and Aspens - are among the species of trees that were exhibiting
the worst air pollution damage long before the storm struck.

A willow badly damaged by the ice storm. Photo by Paul Donahue.

Over the last two years, environmentalists across the state
have focused much attention on the destructive clearcutting and
overcutting of our forests by industry, and rightly so. But as
this storm has made abundantly clear, poor forest management
practices are not the only factors affecting the health of Maine's
forests, and ultimately may not even be the most important factors.
Even if clearcutting, overcutting, the spraying of herbicides
and other poor management practices were to be stopped tomorrow,
there still exists the distinct possibility that Maine's forests
would eventually be destroyed by air pollution.

Back in the 1980's we heard a lot about acid rain and its
effects on mountaintop forests and lakes throughout the northeast,
but since then the issue has largely dropped from the public
eye. In 1990 Congress passed amendments to the Clean Air Act,
which called for reductions in emissions of sulphur dioxide and
nitrogen oxide to deal with the problem of acid rain. With most
Americans' concerns about the problem allayed, the issue largely
slipped from public consciousness. Unfortunately, the 1990 amendments
to the Clean Air Act were not strong enough to sufficiently reduce
acid rain, but even if they had been, acid rain is only one aspect
of the pollution problem facing our trees and forests.

The health of our trees and forests has continued to decline.
The first reports of acid rain damage to trees in the Northeast
dealt with forests on the upper slopes of some of the higher
mountains of the Adirondacks in New York and the Green Mountains
in Vermont. These high peaks are the first to intercept the pollutant-filled
rain clouds arriving from the mid-West, where factories and coal-fired
power plants generate a large part of the pollutants responsible
for acid rain. Now, however, if you know what to look for, the
effects of atmospheric pollutants on our trees can clearly be
seen throughout the region.

Trees generally die from the top down. The first visible symptom
of decline is usually a thinning of the foliage on the uppermost
branches. As the years pass, the tree's crown becomes more and
more transparent. Eventually, dead branches can be seen projecting
from the crown. The foliage begins thinning out in the middle
layers, dead limbs appear, maybe a large limb or two break off
in an ice or wind storm, then the lower foliage begins thinning
out, and finally the tree breaks off or blows over in another
storm. Unfortunately, disastrous ice storms aside, trees generally
die slowly, and, this process can take a decade or more. This
is unfortunate because the change is subtle enough from year
to year to go largely unnoticed.

Acid fog and dead spruce trees along the coast
at West Quoddy Head. Photo by Paul Donahue.

Aside from the mountaintops, the worst pollution-caused tree
damage in Maine can be seen along the coast, and particularly
on exposed headlands and offshore islands. Here the effects of
atmospheric pollutants can be seen with virtually every species
of woody tree and large shrub. Like trees on mountain tops, the
trees on exposed headlands and offshore islands are already exposed
to heavy environmental stresses. On mountaintops the trees have
to deal with strong winds and very cold temperatures while on
the outer coast they have to deal with strong winds and salt
spray. And while the mountaintops are often enveloped in clouds,
the offshore islands are frequently cloaked in fog. The rain
in our area is now three times as acidic as it was in pre-industrial
times, but the coast's abundant fog can be 10 times as acidic
as the rain. The trees in both mountaintop and exposed coastal
environments are already living at their limits and any additional
stress, such as atmospheric pollutants, can be enough to tip
the scales against them.

Two species of northeastern trees, Sugar Maple and Green Ash,
had been hit especially hard even before the ice storm, with
virtually every individual exhibiting the symptoms of slow death.
In southern New England, where Green Ash is more abundant than
it is in Maine, many woodlands have been decimated. It is difficult
now, with all the fresh storm damage, but as you drive Maine's
roads in winter, look for the preponderance of dead limbs on
these two species of trees. Then in summer, look for the transparency
of their crowns. If a Sugar Maple exhibits more than 15% dieback
or more than 55% crown transparency, it can be considered to
be in trouble.

Do you remember back when Sugar Maples would first began to
turn orange in September? As a symptom of their poor health,
now the first orange leaves regularly begin to appear on these
trees in mid-late August.

Both Sugar Maple and Green Ash are commercially valuable trees,
so their loss will be economic as well as aesthetic. Green Ash
provides us with wood for things like tool handles and oars,
while Sugar Maple provides us with a valuable wood, maple syrup,
and the brightest colors in the fall foliage display. Before
the ice storm, some maple syrup producers in Vermont and southern
Ontario had already experienced an 80-100% mortality of their
Sugar Maples. In addition to Sugar Maple and Green Ash, crown-thinning
is especially noticeable on Red Spruce, Red, Silver, and Mountain
Maples, Paper and Heart-leaved Birch Birch, Quaking and Bigtooth
Aspens, and Lombardy Poplar, with a large percentage of the individuals
affected, but the symptoms can be observed on most species of
trees in Maine.

Dead
Paper or Heart-leaved Birch along the upper Bay of Fundy shore
in New Brunswick, an area especially hard-hit by acid rain. Photo
by Paul Donahue.

A Red Spruce along the shore of Casco Bay showing advanced
die-back. Photo by Paul Donahue.

The human-induced pollution problems affecting these trees
are myriad. To start with, the acidity of the rain is caused
mainly by sulphur dioxide, which comes largely from the burning
by power and industrial plants of fossil fuels containing sulphur
and from nitrogen oxide, which comes largely from automobile
exhaust. The sulphur dioxide reacts in the presence of sunlight
to produce sulphuric acid and the nitrogen oxide mixes with moisture
to form nitric acid. When deposited on the soil, these acids
leach away important mineral nutrients in the soil such as calcium,
magnesium, phosphorus and potassium. The acidity also makes toxic
aluminum in the soil more available to the trees.

Ground level ozone, also caused by car exhausts, is another
primary culprit in forest decline. The ozone damages the chlorophyll
in plants, thereby reducing photosynthesis and growth. Another
serious problem is airborne toxic metals, such as cadmium, zinc,
lead, copper, arsenic, barium, chromium, nickel and mercury,
in the rainfall. When materials containing these heavy metals
are incinerated, most of the metals go up the stack and out into
the atmosphere. More mercury enters the atmosphere simply from
burning coal, the same coal that produces sulphur dioxide. The
unnatural acidity of the rain makes these metals more soluble,
more concentrated and more harmful to the plants, damaging their
immune systems.

Then there are substances like pesticides (including herbicides,
chemicals designed to kill plants), carried by the wind from
aerial spraying operations and dioxins from incinerators. To
give some idea of what the trees are dealing with, German researchers
have detected some 400 synthetic organic compounds in a single
cubic meter sample of air! In actuality, our rain and fog have
become a toxic stew, with the pollutants acting synergistically
on our trees in ways we are still far from fully understanding.
Finally, on top of all those threats, there is ultraviolet-B
radiation from the thinning of the ozone layer, yet another suspected
culprit in forest decline.

The results of research at the Hubbard
Brook Experimental Forest (HBEF) in New Hampshire, published
in the 12 April 1996 issue of Science, have disturbing implications
for Maine forests in general. Researchers at HBEF found that
since 1987 forest growth "has declined unexpectedly to a
small rate" due to chemical changes in the soil. The HBEF
is very similar to the forest covering most of northern Maine,
so it is reasonable to assume that similar declines in growth
have occurred here, as well. One of the first measurable effects
of pollution damage to trees is a slowing down in growth. This
occurs well before there are visible signs of damage, so it might
also be reasonable to assume that this decline in growth is just
a first step towards widespread forest death. While this might
seem like a radical statement, this is exactly what has already
happened over large areas of Eastern Europe.

The latest U.S. Forest Service inventory
of Maine forests, published in the summer of 1996, showed
that industrial forests were growing not a half cord per acre
per year, as they have traditionally, but only a sixth of a cord.
This discrepancy has been blamed on industry's management practices,
which have undoubtedly played an important role. But how much
of this difference is due to poor management practices and how
much is due to pollutant-caused slower tree growth? What happens
to forest management plans and our forest products industry if
predictions of tree-growth do not take into account the slower
growth brought on by airborne pollutants?

Weakened trunk of Red Spruce snapped by the wind on a Casco Bay island . Photo by Paul Donahue.

One criticism often leveled by opponents of stricter air pollution
standards is that acid rain or other pollutants don't kill trees,
that they are actually killed by cold winters or by insects or
fungus or some such agent. In a sense these critics are correct
- it is true that cold or insects or fungus or some other pathogen
is often the ultimate cause of tree death rather than pollutants.
But one might fairly ask why in the latter part of this century
are so many pathogens suddenly having such a tremendous effect
on so many species of trees. If just one or two species of trees
were suffering a decline in eastern North America, maybe it would
be acceptable to simply blame the weather or some pathogen and
dismiss the problem as unfortunate but unavoidable. But that
is hardly the case. Instead, what we are witnessing across most
of eastern North America is a pandemic of tree death.

We need to take the wider view and look on these pathogens
as representing only the proximate causes of death, and see forest
decline and tree death across eastern North America for the pandemic
that it is. Our industrial society with its attendant air pollution
is slowly killing our forests, as it has the forests of eastern
Europe, weakening and stressing trees, and making them more susceptible
to cold winters and attack by pathogens.

A good analogy can be made between acid rain and AIDS. You
don't die from the HIV virus, you die of the diseases you contract
because of your depressed immune system. The same holds true
of atmospheric pollutants and trees. It is often not the pollutants
that kill the trees but the insects, viruses, fungi, or bacteria
that attack once the trees' overly-stressed immune systems are
weakened.

There is much that can be done to begin to solve the problem.
To start with, there needs to be much greater media coverage
and public education on the issue. Then, on a personal level,
we can limit our own use of automobiles and other gasoline-burning
vehicles and tools (ORVs, ATVs, snowmobiles, outboard motors,
jet-skis, lawnmowers, leaf-blowers, and chainsaws). Beyond that,
we can push for tighter air quality controls on automobiles and
industry, including incinerators, in Maine. We can also push
for development of a statewide system of public transportation.
And, since much of our air pollution originates from beyond our
state boundaries, we can pressure Congress for tighter federal
air quality controls.

In Germany the term waldsterben - or forest death - is now
a household word. Is that what we want here? Is this trend of
slow forest death what we want for our children's future? To
quote ex-West German Chancellor Helmut Kohl, "If we do not
succeed in saving our forests, the world in which we live will
be changed beyond recognition."